1. Field of the Invention
This invention relates to a solid pharmaceutical preparation containing disodium adenosine triphosphate (hereinafter sometimes referred to briefly as "ATP-2Na"), which is useful, for example, in alleviating or treating cerebrovascular disorder, cardiac failure and asthenopia, and a vitamin B.sub.1 salt or a vitamin B.sub.1 derivative having vitamin B activity, to such solid pharmaceutical preparation stabilized by further addition of a low-melting fat- or oil-like substance, and to a method of producing such composition.
2. Description of Prior Art
Since the discovery by Fiske, Lohmann et al. (1929) of adenosine triphosphate (hereinafter sometimes referred to briefly as "ATP") occurring in muscular tissue infusions, the role of disodium adenosine triphosphate in living organisms has been elucidated step by step by a number of researchers. As a representative of the compounds having the so-called energy rich phosphate bond, ATP is found everywhere in living organisms. The energy required in living organisms is supplied solely by ATP. On the other hand, the clinical use of ATP-2Na as a therapeutic agent has become fairly popular and its efficacy has been established in certain diseases.
On the other hand, vitamin B.sub.1 is known to be effective in the treatment of such diseases as beriberi, neurasthenia, neuritis, neuralgia, edema, congestive heart failure and acute circulatory shock and, accordingly, thiamine disulfide and various other derivatives as well as salts thereof, such as hydrochloride and nitrate, have been synthesized.
It is an object of the invention to provide a pharmaceutical composition with the above-mentioned pharmacological effects of ATP-2Na being potentiated or extended as a result of combined use of another pharmacologically active ingredient with ATP-2Na.
In particular, the invention is to provide an ATP-2Na-containing pharmaceutical composition made more effective in the treatment of asthenopia in view of the current situation in which not a few people complain of asthenopia as a result of the popularized use of various kinds of office automation (OA) equipment. ATP-2Na has drawbacks. Thus, in the solid form, it is unstable under high temperature and/or high humidity conditions and, in the form of an aqueous solution or suspension, its stability decreases with the decreasing pH value. Therefore, preparations or dosage forms containing it, particularly tablets, have poor stability as far as ATP-2Na is concerned. The content of the active ingredient in said preparations decreases with the lapse of time and coloration occurs.
In some pharmaceutical compositions containing other ingredients, ATP-2Na strongly interacts with said other ingredients, leading to still more decreased stability. Furthermore, in the case of tablets, crystals are distorted due to the pressure, friction, heat and other effects applied or produced in the step of molding under pressure and as a result, the fall in content with the lapse of time is accelerated in many instances.
Thus, when ATP-2Na is made up into solid pharmaceutical compositions, for example tablets, stability problems arise. Accordingly, it is a further object of the invention to provide a combination drug composition of practical use which contains ATP-2Na and another active ingredient and in which the decomposition of the active ingredient with the lapse of time is inhibited to a sufficient extent and the stability of ATP-2Na thereby improved.